The present invention relates to a communication apparatus for performing communications via a network.
Conventionally, radio communication systems (PDC: Personal Digital Cellular system, PHS: Personal Handyphone System, and the like) that allow so-called roaming are known. In such system, a radio terminal moves from a service zone served by a telecommunications carrier to which the user himself/herself has subscribed and registered to a service zone served by another telecommunications carrier to perform communication.
Digital automobile telephone systems which download, to the moving terminal, service software (e.g., extension software for displaying charges during speech communication) unique to the roaming destination area in position registration processing are also known. In a digital automobile telephone system, however, the user is not informed of extension software unless the terminal registers its position. Additionally, in a digital automobile telephone system, services which require user""s operation for reception of services provided by extension software are not taken into consideration.
It is an object of the present invention to provide a communication apparatus with good operability.
It is another object of the present invention to provide a communication apparatus which can be operated as in connection to a first network even in connection to the second network.
It is still another object of the present invention to notify a user that he/she cannot use a service.
It is still another object of the present invention to notify a communication terminal of a changed operation procedure for a service provided by a network when the operation procedure is changed.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.